We present a simple method for analyzing the impact of precision electroweak data above and below the Z peak on flavor-conserving, heavy new physics. We find that experiments have probed about ten combinations of new-physics effects, which to a good approximation can be condensed into the effective oblique parameters S, T, U, V, X, W, Y (we prove positivity constraints W,Y >= 0) and three combinations of quark couplings (including a distinct parameter for the bottom). We apply our method to generic extra Z(') vectors

We perform a thorough analysis of oscillation signals generated by one extra sterile neutrino, extending previous analyses done in simple limiting cases and including the effects of established oscillations among active neutrinos. We consider the following probes: solar, atmospheric, reactor and beam neutrinos, big-bang nucleosynthesis (helium-4, deuterium), cosmic microwave background, large scale structure, supernovae, neutrinos from other astrophysical sources. We find no evidence for a sterile neutrino in present data, identify the still allowed regions, and study which future experiments can best probe them: sub-MeV solar experiments, more precise studies of CMB or BBN, future supernova explosions, etc. We discuss how the LSND hint is strongly disfavoured by the constraints of (standard) cosmology. (C) 2004 Elsevier B.V. All rights reserved

We examine a scenario where the new physics at the LHC includes an approximate conformal field theory, where some of the degrees of freedom (aka "unparticles") carry a color charge. We present a simple argument showing that the production cross section for scalar unparticles mediated by a gauge interaction is given by 2 − d times the standard particle expression, where d is the scaling dimension of the unparticle field. We explicitly check that this is indeed the case, which involves non trivial cancellations between different Feynman diagrams, for the process qq → scalar unparticles.

We present a class of models that contains Randall-Sundrum and Higgsless models as limiting cases. Over a wide range of the parameter space W W scattering is mainly unitarized by Kaluza-Klein partners of the W and Z, and the Higgs particle has suppressed couplings to the gauge bosons. Such a gaugephobic Higgs can be significantly lighter than the 114 GeV LEP bound for a standard Higgs, or heavier than the theoretical upper bound. These models predict a suppressed single top production rate and unconventional Higgs phenomenology at the LHC: the Higgs production rates will be suppressed and the Higgs branching fractions modified. However, the more difficult the Higgs search at the LHC is, the easier the search for other light resonances (like Z ′ , W ′ , t ′ , exotic fermions) will be.